Syntenic (linkage) maps of over 20 mammalian species and a comparative cytological analysis have indicated a noncontinuous tempo of chromosomal evolution in certain lineages (e.g., primates, felids) that are highly conserved in their chromosomal presentation, while others (rodents, lesser apes, canids) are chromosomally shuffled as if rapid altatory cytological rearrangements occurred during the special events. The abundant fibroblast proteins resolved by two-dimensional gel electrophoresis (2DE) in human materials have been studied to (1) identify specific proteins, enzymes and previously characterized gene products; (2) define allelic variation at polymorphic loci for use in pedigree analysis and assessment of genetic structure of outbred populations. A molecular phylogeny of the great and lesser apes and man was derived based on genetic distance of 383 different proteins resolved by 2DE. The South African subspecies of cheetah was shown to be genetically depauperate insofar as it is monomorphic at 52 isozyme loci. Unrelated cheetahs also accepted skin grafts, a situation without precedent among outbred mammalian species. A devastating epizootic of the species by feline infectious peritonitis (FIP and RNA containing corona virus) was hypothesized to result from abrogation of a major histocompatibility complex (MHC) haplotype in T-cell stimulation. A molecular phylogeny of the 37 species of the Felidae was constructed based on immunological distance using serum albumin. Similarly, a consensus phylogeny of the Ursidae Ailuropoda (giant panda) and Ailurus (lesser panda) was derived from distance matrices derived from three distinct molecular measures of genetic distance.